Sandström Mattias, Lindskog Karolina, Velikyan Irina, Wennborg Anders, Feldwisch Joachim, Sandberg Dan, Tolmachev Vladimir, Orlova Anna, Sörensen Jens, Carlsson Jörgen, Lindman Henrik, Lubberink Mark
Nuclear Medicine and PET, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
Nuclear Medicine and PET, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
J Nucl Med. 2016 Jun;57(6):867-71. doi: 10.2967/jnumed.115.169342. Epub 2016 Feb 9.
(68)Ga-ABY-025 is a radiolabeled Affibody molecule for in vivo diagnosis of human epidermal growth factor receptor 2 (HER2)-positive breast cancer tumors with PET. The aim of the present work was to measure the biodistribution and estimate the radiation dosimetry of (68)Ga-ABY-025 for 2 different peptide mass doses in a single group of patients using dynamic and serial whole-body PET/CT.
Eight patients with metastatic breast cancer were included. Each patient underwent an abdominal 45-min dynamic and 3 whole-body PET/CT scans at 1, 2, and 4 h after injection of a low peptide dose (LD) and a high peptide dose (HD), with approximately the same amount of radioactivity, in separate investigations 1 wk apart. As input to the absorbed dose calculations, volumes of interest were drawn on all clearly identifiable source organs: liver, kidneys, spleen, descending aorta, and upper large intestine. Absorbed doses were calculated using OLINDA/EXM, version 1.1.
Of the major organs, the highest radionuclide uptake at 1, 2, and 4 h after injection was observed in the kidneys and liver. The highest absorbed organ doses were seen in the kidneys, followed by the liver for both LD and HD (68)Ga-ABY-025. Absorbed doses to liver and kidneys were slightly but significantly higher for LD. Total effective dose was 0.030 ± 0.003 mSv/MBq for LD and 0.028 ± 0.002 mSv/MBq for HD.
The effective dose for a typical 200-MBq administration of (68)Ga-ABY-025 is 6.0 mSv for LD and 5.6 mSv for HD. Therefore, from a radiation dosimetry point of view, HD is preferred for PET/CT evaluation of HER2-expressing breast cancer tumors. These effective doses are somewhat higher than earlier published values for other (68)Ga-labeled tracers, such as 0.021 ± 0.003 mSv/MBq for (68)Ga-DOTATATE and (68)Ga-DOTATOC, mainly because of higher uptake in liver and kidney.
（68）Ga-ABY-025是一种放射性标记的亲和体分子，用于通过PET对人表皮生长因子受体2（HER2）阳性乳腺癌肿瘤进行体内诊断。本研究的目的是使用动态和系列全身PET/CT测量一组患者中两种不同肽质量剂量的（68）Ga-ABY-025的生物分布，并估算其辐射剂量学。
纳入8例转移性乳腺癌患者。每位患者在注射低肽剂量（LD）和高肽剂量（HD）后1、2和4小时分别进行一次45分钟的腹部动态PET/CT扫描和3次全身PET/CT扫描，两次检查间隔1周，放射性活度大致相同。作为吸收剂量计算的输入，在所有清晰可辨的源器官（肝脏、肾脏、脾脏、降主动脉和上段大肠）上绘制感兴趣区。使用OLINDA/EXM 1.1版计算吸收剂量。
在主要器官中，注射后1、2和4小时肾脏和肝脏的放射性核素摄取最高。LD和HD（68）Ga-ABY-025的最高器官吸收剂量均出现在肾脏，其次是肝脏。LD的肝脏和肾脏吸收剂量略高但有显著差异。LD的总有效剂量为0.030±0.003 mSv/MBq，HD为0.028±0.002 mSv/MBq。
典型的200 MBq（68）Ga-ABY-025给药的有效剂量，LD为6.0 mSv，HD为5.6 mSv。因此，从辐射剂量学角度来看，HD更适合用于PET/CT评估HER2表达的乳腺癌肿瘤。这些有效剂量略高于其他（68）Ga标记示踪剂的早期公布值，如（68）Ga-DOTATATE和（68）Ga-DOTATOC的0.021±0.003 mSv/MBq，主要是因为肝脏和肾脏摄取较高。
